test(node-integration-tests): Fix flaky postgresjs basic transaction/error ordering

[github-actions]

Fixes the flaky postgresjs auto instrumentation > basic > should auto-instrument \postgres` package [esm]` Node integration test.

Root cause

The basic test is the only postgresjs test that expects two differently-typed envelopes — a transaction followed by an error event:

.expect({ transaction: EXPECTED_TRANSACTION })
.expect({ event: EXPECTED_ERROR_EVENT })

The scenario's final query targets the just-dropped "User" table, so it rejects with a PostgresError. That rejection propagates out of run() as an unhandled promise rejection, which Sentry captures on a later event-loop tick than the transaction (the transaction is captured synchronously when the root span ends). Because the two envelopes are produced on different ticks, their arrival order at the transport is not deterministic.

By default the test runner matches envelopes in order (expectedEnvelopes.shift()), so whenever the error event happened to reach the transport before the transaction, the runner threw Expected envelope item type 'transaction' but got 'event' and the test failed — a textbook intermittent flake. The other three describe blocks each expect only a single transaction envelope, which is why only basic flaked.

Fix

Add .unordered() to the basic runner chain so the two envelopes may arrive in either order. Both the transaction (with all its spans) and the error event are still fully asserted with the same content matchers — only the brittle arrival-order constraint is removed. This mirrors the existing precedent in suites/tracing/apollo-graphql/test.ts, which uses .unordered() for the same class of non-deterministic multi-envelope ordering.

Fixes #21790